Voltage regulator relay system



Aug. 26, 1941. J KQVALSKY 2,254,039.

VOLTAGE REGULATOR RELAY SYSTEM Filed Jam 13, 1938 WITNESSES:

g j I INVENTOR I Patented Aug. 26, 1941 VOLTAGE REGULATOR RELAY SYSTEMJoseph F. Kovalsky, Turtle Creek, Pa., assignor to Westinghouse Electric8: Manufacturing Company, East Pittsburgh, Pa.', a corporation ofPennsylvania Application January 13, 1938, Serial No'. 184,839

Claims.

My invention relates to regulator systems and particularly to thecontrol mechanism for governing the operation of rheostatic typeregulators. In rheostatic type regulators, it is customary to providearheostat operating motor that is controlled by secondary or motorreversing switches that are, in turn, controlled by a primary relay thatis actuated in accordance with variations in the quantity to beregulated, such as the voltage of a generator.

In delicate instruments, such as contact-making voltmeters thatconstitute the primary relays of voltage regulators, the floatingcontact members approach their cooperating contact members slowly andengage initially with very slight pressure. The contact surfaces of theengaging contact members are small and may become dirty bytheaccumuiation of foreign matter, such as dust, which tends to form ahigh resistance filmon the surface of the contacts, and which may limitthe current passing therethrough to a value that is insufficient tocause the operation of the associated motor operating switch to itscircuit closing position with the slight contact pressure normallyprevailing at the initial engagement of the floating contact members ofthe primary relay with their cooperating contact members.

It is an object of my invention to provide means for causing sufficientcontact pressure between the contact members of the primary relay of aregulator to assure operation of the regulating mechanism upon slightinitial contact pressure of the contact members.

It is a further object of my invention to provide means for assuringpositive contact pressure between the contact members of the primaryrelay of a regulator without disturbing the accuracy of the regulatoraction.

Referring to the drawing, the single figure is a diagrammatic view ofapparatus and circuits comprising one preferred embodiment of theinvention.

In the drawing, a direct-current generator is illustrated having anarmature winding l for supplying electrical energy to a circuitrepresented by conductors 2 and 3, and a field winding 4 that issupplied with excitation current from an exciter generator having anarmature winding 5 and a field winding 6 that is connected in shuntrelation to the armature winding 5 through a variable resistor l. Theexciter generator armature 5 is connected to the generator field winding4 by conductors 8 and 9 through a rheostat I 2 having a resistor l3 anda movable arm [4 for varying the effective resistance in series with thefield winding 4 in accordance with the operation 01' a pilot motor l5that actuates the arm l4 through a gearing mechanism l6. The motor l5comprises an armature winding 11 connected to the motor shaft, anddifferentially related field windings I 9 and I9 that are adapted to beconnected to a source of electrical energy represented by battery 22upon the closing 0! the one or the other of two motor reversing switches23 and 24 as controlled by a primary relay 25.

The primary relay 25 comprises a movable lever 26 that is pivotallysupported at one end 2'! and provided at the other end with floatingcontact members 28 that are adapted to engage cooperating contactmembers 29 and 32 in accordance with the movement of the lever 26 thatis biased in one direction by a spring 33 and in the opposite directionby a magnet having a core 34 connected to the arm 26. The core 34 isenergized by an operating winding 35 that is connected by conductors 36and 31 to the circuit conductors 2 and 3, respectively, to be energizedin accordance with the voltage output of the generator armature l. Therelay contact members 29 and 32 are carried, respectively, by levers 38and 39 mounted upon supporting pivots 42 and 43, and connected by a link44 extending between pivot points 45 and 46, so as to move the contactmembers 32 and 34 in opposite direction. Stops 41 and 43 are providedfor limiting the movement of the contact carrying ends of the levers 33and 39 toward each other under the influence of a spring 49 provided forthat purpose. An armature 52 is provided on the lever 39 that isinfluenced by a magnet 53 to move the contact members 32 and 34 in amanner to be presently described.

If the voltage between conductors 2 and 3 drops below the value forwhich the primary relay 25 is adjusted, the upward pull on the winding35 decreases sufliciently that the spring 33 pulls the lever 26downwardly to cause engagement between contact members 23 and 32 toclose an operating circuit for the motor reversing switch 23. Thiscircuit extends from one terminal of a source of energy represented bythe-positive conductor 54 through the relay contact members 23 and 32,conductor 55, an auxiliary winding 56 provided about the core 34 of theprimary relay 25, through conductor 51, winding 58 of the reversingswitch 23, and conductor 59 to the other terminal of the source ofenergy represented by the negative conductor 62.

auxiliary winding 66 about the core 34 is energized and acts oppositelyto the winding 35 to increase the contact pressure between contactmembers 28 and 32 to increase the flow of current through the auxiliarywinding 56 and through the operating winding 58 of the motor reversingswitch 23. If the pressure of the initial engagement between the contactmembers 28 and 32 is insuilicient to supply the current necessary foractuating the reversing switch 23 to its circuit closing position, theincrease in contact pressure caused by flow of current through thewinding 56 will assure the building up of current in the winding 58 to avalue to cause operation of the switch 23 to its circuit closingposition.

The closing of the switch 23 causes a circuit to be completed from oneterminal or the battery 22 through conductor 65, the switch contactmembers 66 and 61, the field winding 18, the motor armature winding llto the other terminal of the battery 22 to operate the motor l5 to movethe rheostat arm l4 in a counterclockwise direction to decrease thatportion of the rheostat resistor 13 that is in circuit with the fieldwinding 4, and thus increase the energization of the field winding 4 andof the generator armature I.

A condenser 63 is provided, connected in series with a resistor 64 inparallel circuit relation with the winding 58 of the reversing switch 23to provide a timing circuit for holding the reversing switch 23 closedfor a predetermined time after interruption of the energizing circuitwhich is effected by the discharge of the condenser 63 through thewinding 58. The charging of the condenser 63 takes place during thebuilding up of the current in the winding 58 to a value suilicient tocause it to operate the switch 23 to its circuit closing position.

At the same time that the contact member 61 bridges the contact members66, the contact member 13 bridges the contact members 12 to close acircuit from conductor 54 through conductor 68, the winding of themagnet 53, conductor 69, the contact members 12 and 13 of the reversingswitch 23 and conductor 59, to energize the magnet 53 causing thearmature 52 to be pulled downwardly and toward the left, as

viewed in the drawing about the pivot 43, to

move the lever 39 away from the stop 48 and the contact member 32 fromengagement with the contact member 28. This operation permits thereversing switch 23 to be deenergized and dropped to its circuitinterrupting position after the time interval provided by the condenser63, which time interval insures sufficient operation of the rheostatmotor 15 to cause the rheostat arm 14 to move from engagement with onerheostat button to the next adjacent button in a well known manner. Ifthe drop in voltage of the generator armature I is very large, thecontact member 28 may engage the contact member 32 in its lower positionuntil the increase in voltage of the generator armature I has progressedsufficiently to cause upward movement of the lever 26.

In a similar manner, if the voltage between conductors 2 and 3 increasesabove the desired value, the increase in the pull of the winding 35 onthe core 34 will move the magnet core upwardly against the force of thespring 33 and cause engagement of contact members 28 and 29 to close acircuit from conductor 54 through contact members 28 and 29, conductor14,

auxiliary winding I5 provided about the core 34 or the primary relay,conductor I6, the winding 11 of the reversing switch 24, and conductor16 to the negative conductor 62. The closing of this circuit causesoperation of the reversing switch 24 to its circuit closing position, toclose a circuit from one terminal of the battery 22 through the contactmembers 19 and 82, the motor field winding l9 and armature winding I! tothe other terminal of the battery 22 to energize the motor to operatethe rheostat arm I4 in a clockwise direction to thereby insert a greaterportion of the resistor I3 in series with the generator field winding 4to decrease the energization thereof and correspondingly decrease thevoltage output of the armature I. Upon initial engagement of the contactmembers 28 and 29, the current flowing through the circuit controlledthereby and which includes the winding 15 on the primary relay, causesthe winding 15 to aid the pull of the operating winding 35, to increasethe upward pull of the core 34 on the lever 26 and increase the contactpressure between the contact members 28 and 29. If, therefore, thepressure of the initial engagement between the contact members 28 and 29is insufficient to supply the current necessary for actuating thereversing switch 24 to its circuit closing position, the increase incontact pressure caused by flow of current through the winding 15 willassure the building up of current in the winding IT to a value that willcause operation of the switch 24 to its circuit closing position. Atiming'circuit consisting of a condenser 63 and a resistor 64 connectedin series with each other is provided in shunt relation to the reversingswitch winding 1'! in the same manner as for the reversing switch 23 tomaintain it in its circuit closing position for a predetermined timeafter interruption of the circuit energizing the winding 11.

Upon operation of the switch 24 to its circuit closing position, acircuit is also closed from conductor 54 through conductor 68, thewinding of magnet 53, conductor 69, contact members 83 and 84 andconductor 18 to conductor 62 for energizing the magnet 53 to operate thelevers 39 and 38 in the manner above-described to move the contactmembers 28 and 29 away from each other, thus separating the contactmembers 28 and 29 to interrupt the circuit through the winding ll ofthe' reversing switch 24. This provides an anti-hunting action toprevent overtravel of the rheostat arm l4 in either direction.

In the above-described regulator, it will be appreciated that theoperation of the regulator is improved by providing means for increasingthe contact pressure after initial engagement 0! the contact members ofthe primary relay until the associated motor operating switch isoperated to a circuit closing position after which the energizingcircuit thereof is abruptly interrupted by movement of the outer contactmember 29 r and 32, thus reestablishing the initial conditions at makingvoltmeter,

acumen since the windings It and I! are not energized during the normaloperation of the relay, which is under the control of the winding 35.The winding 56 or 15 is deenergized' immediately upon energization ofthe coil of the anti-hunting magnet 53 as above-described, the closedreversing switch being held in its circuit closing position for a shorttime thereafter by operation of the associated capacity timing circuit.

actuated thereby adapted to engage the one orthe other of twocooperating contact members for controlling circuits for energizing theone or the other of said reversing switches, means energized in responseto engagement of said cooperating primary relay contact members withlight pressure for causing a sumcient increase in contact pressure toassure operation of the associated reversing switch, said meanscomprising a pair of coils, one of said coils being effective to opposethe operating coil when the floating contact means engages one of saidcooperating contact members, and the other or said coils being effectiveto aid the operating coil when the floating contact means engages theother of said cooperating contact members.

2. In a regulator system wherein an electric motor and means actuatedthereby are employed for varying a quantity to be regulated, incombination, a pair of electrically operated reversing switches actuatedto their circuit closing positions when energized, a primary relay forcontrolling the reversing switches having floating contact means and twocooperating contact members adapted to be separately engaged by saidfloating contact means for controlling circuits for energizing the oneor the other of said reversing switches, means for actuating saidfloating contact means comprising an electromagnet having an operatingcoil and a coil in series with each cooperating contact member formodifying the pull of the magnet upon closure of a circuit by saidcontact member for assuring positive contact pressure, one of said coilsin series with a cooperating contact member being arranged to actdifferentially with the operating coil controlling the floating contactmeans upon engagement of the floating contact means with said onecooperating contact member, and the other of said coils in series with acooperating contact member being arranged to act cumulatively with theoperating-coil controlling the floating contact means upon engagement ofthe floating contact means with said other cooper-' the other of twocooperating contact members for controlling circuits for energizing theone or the other of said reversing switches, means comprising a pair ofcoils responsive to engagement of said cooperating primary relay contactmembers with light pressure for causing a sufficient increase'in contactpressure to assure operation of the associated reversing switch, one ofsaid i coils being effective to oppose the operating coil ated therebyand adapted to engage the one or when the floating contact means engagesone of said cooperating contact members, and the other of said coilsbeing effective to aid the operating coil when the floating contactmeans engages the other of said cooperating contact members, andelectrically actuated means for separating the primary relay contactmembers, said last-named means being energized through auxiliary contactmembers on said reversing switches upon operation thereof to circuitclosing positions.

4. In a regulator system wherein an electric motor and'means actuatedthereby are employed for varying a quantity to be regulated, incombination, a pair of electrically operated reversing switches actuatedto their circuit closing positions when energized, a primary relayhaving floating contact members and an electromagnet having an operatingcoil for actuating said floating contact members, cooperating contactmembers adapted to be separately engaged by said floating contactmembers to control circuits for controlling the operation of saidreversing switches, electro-responsive means comprising a pair of coilscontrolled by-engagement of said primary relay contact members forincreasing the contact pressure to assure operation of said reversingswitches, one of said coils being effective to oppose the operating coilwhen the floating contact means engages one of said cooperating contactmembers, and the other of said coils being effective to aid theoperating coil when the floating contact means engages the other of saidcooperating contact members, and electro-responsive means controlled byoperation of said reversing switches for'causing separation of saidprimary relay contact members.

5. In a regulator system wherein an electric motor and means actuatedthereby are employed for varying a quantity to be regulated, incombination, a pair of electrically operated reversing switches actuatedto their circuit closing positions when energized, a primary relayhaving floating contact means adapted to engage the one or the other oftwo cooperating contact members for controlling energizing circuits forenergizing the one or the other of said reversing switches and a magnetcomprisinga core and three windings thereon, one of said windings beingan operating winding for controlling the operation of said floatingcontact means and the other windings being auxiliary windings connectedin series with the cooperating contact members of the primary relay forincreasing the contact pressure upon engagement thereof with lightpressure for causing a sufiicient increase in contact pressure to assureoperation of the as sociated reversing switch, one of said auxiliarywindings being arranged to aid and the other to oppose the operatingwinding and electricallyactuated means for separating the primary relaycontact members, said last-named means being energized through auxiliarycontact members on said reversing switches upon operation thereof tocircuit closing positions.

JOSEPH F. novel-stir.

